Limitations in Predicting the Space Radiation Health Risk for Exploration Astronauts

Despite years of research, understanding of the space radiation environment and the risk it poses to long-duration astronauts remains limited. There is a disparity between research results and observed empirical effects seen in human astronaut crews, likely due to the numerous factors that limit terrestrial simulation of the complex space environment and extrapolation of human clinical consequences from varied animal models. Given the intended future of human spaceflight, with efforts now to rapidly expand capabilities for human missions to the moon and Mars, there is a pressing need to improve upon the understanding of the space radiation risk, predict likely clinical outcomes of interplanetary radiation exposure, and develop appropriate and effective mitigation strategies for future missions. To achieve this goal, the space radiation and aerospace community must recognize the historical limitations of radiation research and how such limitations could be addressed in future research endeavors. We have sought to highlight the numerous factors that limit understanding of the risk of space radiation for human crews and to identify ways in which these limitations could be addressed for improved understanding and appropriate risk posture regarding future human spaceflight.Comment: Accepted for publication by Nature Microgravity (2018

A Risk Based Approach to Node Insertion within Social Networks

Social Network Analysis (SNA) is a primary tool for counter-terrorism operations, ranging from resiliency and influence to interdiction on threats stemming from illicit overt and clandestine network operations. In an ideal world, SNA would provide a perfect course of action to eliminate dangerous situations that terrorist organizations bring. Unfortunately, the covert nature of terrorist networks makes the effects of these techniques unknown and possibly detrimental. To avoid potentially harmful changes to enemy networks, tactical involvement must evolve, beginning with the intelligent use of network in filtration through the application of the node insertion problem. The framework for the node insertion problem includes a risk-benefit model to assess the utility of various node insertion scenarios. This model incorporates local, intermediate and global SNA measures, such as Laplacian centrality and assortative mixing, to account for the benefit and risk. Application of the model to the Zachary Karate Club produces a set of recommended insertion scenarios. A designed experiment validates the robustness of the methodology against network structure and characteristics. Ultimately, the research provides an SNA method to identify optimal and near-optimal node insertion strategies and extend past node utility models into a general form with the inclusion of benefit, risk, and bias functions

Using the J1-J2 Quantum Spin Chain as an Adiabatic Quantum Data Bus

This paper investigates numerically a phenomenon which can be used to transport a single q-bit down a J1-J2 Heisenberg spin chain using a quantum adiabatic process. The motivation for investigating such processes comes from the idea that this method of transport could potentially be used as a means of sending data to various parts of a quantum computer made of artificial spins, and that this method could take advantage of the easily prepared ground state at the so called Majumdar-Ghosh point. We examine several annealing protocols for this process and find similar result for all of them. The annealing process works well up to a critical frustration threshold.Comment: 14 pages, 13 figures (2 added), revisions made to add citations and additional discussion at request of referee

Crowdsourcing field observations from smallholder farmers in Tanzania using interactive voice response

The term crowdsourcing was first used in 2006 but the approach has been employed in various fields over a much longer period of time. The central idea is to collect information from a large number of people in order to achieve a common goal such as to increase knowledge, solve a problem or enhance the efficiency of a process. In the realm of research, crowdsourcing is closely connected with citizen science in which members of the public are engaged in a scientific project. In C17th England, the naturalist John Ray arranged for a large number of volunteers to collect specimens for him and there are datasets on the phenology of plants, birds and insects in England and in some other countries which provide a continuous record for hundreds of years. A current example of how non-specialists are helping to gather large quantities of biological data is the Breeding Bird Survey run by the British Trust for Ornithology which engages thousands of volunteers to submit records of over 200 bird species each year. Although crowdsourcing has been widely used in environmental monitoring there are few examples of its use in agriculture. This is surprising because there is a tradition of participatory approaches to agricultural research which have been developed in recent decades. The potential for harnessing large numbers of individual farmers to generate information on the performance of crop varieties in different locations was recently demonstrated through a triadic comparison of technologies. This was taken a stage further in a subsequent study in which a total of 12,409 farmers collected data on experimental plots of common bean (Phaseolus vulgaris) in Nicaragua, durum wheat (Triticum durum) in Ethiopia, and bread wheat (Triticum aestivum) in India. The results showed that expected effects of seasonal climatic variables on the performance of the crop varieties occurred and that these were generalizable across growing seasons. The authors concluded that their approach allows for more targeted recommendations for the deployment of crop varieties and that these may differ substantially from recommendations derived from current evaluation procedures in which testing is done at a limited number of sites. Crowdsourcing has tremendous potential for use in insect pest management. Up to date information on the distribution and abundance of insect pests of crops is needed for the development of appropriate management strategies. Field surveys can be used to identify locations where pest levels are high and sequential monitoring may help to establish seasonal patterns of occurrence. Surveys are also useful in monitoring the likely sources of migrant pests and recording their dispersal from these areas. When used in combination with other information such as climatic data, field surveys are an essential element of insect pest forecasting systems. In developing countries, field surveys are generally conducted by agricultural research and extension staff. Their main limitation is that they are labour-intensive and costly to carry out. Since resources of manpower and funds are limited, surveys are carried out infrequently and in restricted locations which may not be representative of the situation over larger areas. As a result national agricultural research and extension systems are constrained by having limited access to accurate information on the status of insect pests in different locations. This makes it difficult for them to respond to new threats such as the recent appearance and spread of the fall armyworm (Spodoptera frugiperda) in Africa where monitoring and early warning systems are crucial for effective control

Practical designs for permutation-symmetric problem Hamiltonians on hypercubes

We present a method to experimentally realize large-scale permutation-symmetric Hamiltonians for continuous-time quantum protocols such as quantum walks and adiabatic quantum computation. In particular, the method can be used to perform an encoded continuous-time quantum search on a hypercube graph with 2n vertices encoded into 2n qubits. We provide details for a realistically achievable implementation in Rydberg atomic systems. Although the method is perturbative, the realization is always achieved at second order in perturbation theory, regardless of the size of the mapped system. This highly efficient mapping provides a natural set of problems which are tractable both numerically and analytically, thereby providing a powerful tool for benchmarking quantum hardware and experimentally investigating the physics of continuous-time quantum protocols

A Method for Estimating the Current and Future Carbon Content of Standing Biomass Applied to Gishwati Forest Reserve, Rwanda

The carbon content of standing tree biomass was determined in the Gishwati Forest Reserve in north-western Rwanda and growth potential of the forest was estimated using a straightforward, generalisable model of natural forest regeneration. A survey was conducted on 2289 trees in plots throughout the reserve. Wood density data were obtained from literature and tree biomass was estimated using a recent pan-tropical allometric equation. A survey on United Nations Framework Convention on Climate Change (UNFCCC) Clean Development Mechanism (CDM) projects showed that current methods of growth rate projection for mixed, non-plantation forests might significantly overestimate the amount of carbon sequestered. The current study identified an alternative potential method for the estimation of sequestration rates that did not depend upon compiling single-species growth rates and reduced the risk that error would lead to significant over- or underestimation of total biomass sequestration potential. This method used remote-sensing data to estimate total biomass potential in a mature forest based upon local samples and assumes a standard growth trajectory based upon literature values. The benefits in terms of accuracy and ease of model construction are likely to be high. It was found that tree biomass in Gishwati forest contained 53.9 ± 10 CO2 equivalent(e) ha-1 and was expected to sequester an average of 1.01 (0.80–1.38) Mg CO2e ha-1 per annum over the next 30 years

Examining barriers, motivations, and perceptions of women working in the tourism industry: Case study of Ayampe, Ecuador

The notion of examining gender is gaining momentum across disciplines as an important phenomenon to understand (Kincheloe & Mclaren, 2008). The tourism field is one such area that has made sizeable contributions to the literature; however there is a lack of research focusing on women and tourism in developing countries. This is an exploratory case study of a rural community in Ecuador. Using community-based research methodology and a gender and development framework, this study explores the motivations, barriers and perceptions towards women seeking employment in the tourism industry and identified disparities between the perceptions of men and women in regard to the potential for women securing employment in the industry. The themes that emerged from the data may be grouped as those indicating barriers: gender role expectations, machismo, and poor education; and as motivators: economic benefits, opportunity to learn new things, purpose in life, and education for their children

Algorithm for Dual-Energy Radiographic Analysis

The use of two or more radiographs of an object taken with different x-ray spectral characteristics to infer quantitative values of material density or Z number has been of interest to both the medical and industrial worlds for some time. One method uses monoenergetic isotopic sources with well defined energies in conjunction with standard step wedges and solving the resulting simultaneous equations. Besides the problem of finding isotopic sources with the appropriate energies, you have to have a priori knowledge of the materials in the object